Question

What will be the volume of$17g$of$N{H_3}$at N.T.P?

Answer 1

Hint : The mole concept is very significant and useful in chemistry. It is actually the base of stoichiometry and it provides the best option to express the amounts of reactants as well as products that are consumed and formed during a chemical reaction.

Complete Step By Step Answer:
We know that NTP is Normal Temperature and Pressure which is defined a temperature of ${20^0}C$ and$1$atmosphere. We also know that, $1$mole of gas occupies$22.4L$at normal temperature and pressure. Number of moles, ‘n’ can be calculated using the following formula:
$n = \dfrac{m}{M}$
m = given mass
M = molar mass
In the given question, we are provided with the following information:
Given mass of$N{H_3}$=$17g$
The molar mass of any compound can be found out by adding the relative atomic masses of each element present in that particular compound. We know the atomic mass of nitrogen and hydrogenn which is mentioned below:
$\begin{gathered} N = 14.0067u \\\ H = 1.00784u \\\ \end{gathered}$
The molar mass of$N{H_3}$can be easily calculated by adding the mass of one nitrogen atom and three hydrogen atoms as shown below:
$\begin{gathered} Molar{\text{ }}mass{\text{ }}of{\text{ }}N{H_3} = (1 \times N) + (3 \times H) \\\ = (1 \times 14.0067) + (3 \times 1.00784) = 17.03022 \simeq 17gmo{l^{ - 1}} \\\ \end{gathered}$
Now substituting these values in the aforementioned formula for number of moles, we get:
$n = \dfrac{{17}}{{17}} = 1$
Thus, the volume of$17g$of$N{H_3}$at N.T.P is $22.4L$.

Note :
We can use the formula of molarity also to determine the number of moles present in the sample.
Thus,$Number{\text{ }}of{\text{ }}moles = Molarity(M) \times Volume(V)$
Don’t get confused between molarity and molality. Molarity is the number of moles of solute per volume of solution (litres) while Molality is the number of moles of solute per weight of solvent (kilogram).